Alekhina is currently serving a two-year prison sentence in Russia after being found guilty of “hooliganism motivated by religious hatred or hostility” stemming from a protest at Moscow’s Christ the Saviour Cathedral.

The Associated Press reports that prior to her hospitalization, Alekhina published a letter through her lawyer, in which she claimed prison officials were attempting to turn fellow inmates against her in advance of her hearing.

Earlier this year, Alekhina was sentenced to five months in solitary confinement after claiming prison officials deliberately placed her in the same cell as a convicted murder. Her lawyer also filed complaints after prison officials failed to punish inmates who threatened Alekhina with violence, and after officials wrote false psychiatric reports about her.